Question: Mildred, of Mildred’s Tool and Die Shop, is faced with a decision regarding the shop’s central tool cage. She is considering three alternatives:

a. The cage is currently manned by a single clerk, who takes an average of 5 minutes to check and carry parts to each machinist who requests them. The machinists arrive every 8 minutes on the average. Times between arrivals and for service are assumed to both have exponential distributions. A machinist’s time is valued at $15 per hour; a clerk’s time is valued at $9 per hour.

b. Use two clerks who are equally fast. There would still be a single waiting line.

c. Have a machinist instead of a clerk operate the tool cage. Special knowledge enables the machinist to provide service twice as fast as the clerk.

What do you recommend and why?